<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta http-equiv="X-UA-Compatible" content="IE=edge">
	<title></title>
	<link rel="stylesheet" href="">
</head>
<body onload="startTime()">
	<script type="text/javascript">
		var str ="hello world";
		// document.write(str.match("world"));
		// document.write(str.replace("world", 'string'));
		// document.write(str.toUpperCase());
		// var date =new Date();
		// document.write(date);
		// document.write(date.getTime());
		function startTime () {
			 var today = new Date() ;
			 var h = today.getHours();
			 var m =today.getMinutes();
			 var s = today.getSeconds();
			 h = checkTime(h);
			 m = checkTime(m);
			 s=checkTime(s);
			 document.getElementById("timetxt").innerHTML=h+":"+m+":"+s;
			 t = setTimeout(function () {
			 	 startTime();
			 }, 100);
		}
		function checkTime (i) {
			 if(i<10){
			 	i="0"+i;
			 } 
			 return i;
		}
	</script>
	<div id="timetxt">
		
	</div>
</body>
</html>